/* CSS Document */
 *{margin: 0;padding: 0; list-style: none; text-decoration: none;}
        .fourthly{
            margin-top: 500px;
            width: 100%;
            height: 700px;
            border: 1px solid;
        }
        .fourthly header{
            width: 500px;
            height: 90px;
            background: #f7f7f7;
            border-radius: 40px;
            margin: 30px auto;
        }
        .fourthly header h1{
            margin-left: 25px;
        }
        .fourthly p{
            text-align: center;
            font-size: 20px;
        }
        .fourthly nav{
            width: 100%;
        }
        .fourthly nav ul{
            width: 1200px;
            background: #f7f7f7;
            border-radius: 200px;
            margin: 40px auto;
        }
        .fourthly nav ul li{
            display: inline-block;
            position: relative;
            width: 212px;
            height: 212px;
            border-radius: 50%;
            margin-left: 65px;
            box-sizing: border-box;
        }
        .fourthly nav ul li img:nth-child(1){
            margin: 60px 0 0 15px;
            transition: .2s ease-in;
        }
        .fourthly nav ul li img:nth-child(2){
            position: absolute;
            left: 0;
            top: 0;
            opacity: 0;
            transform: scale(0);
            transition: .2s ease-in;
        }
        .fourthly nav ul li:hover img:nth-child(1){
            transform: scale(0);
        }
        .fourthly nav ul li:hover img:nth-child(2){
            opacity: 1;
            transform: scale(1);
        }
